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起重机增容后主小车轨道压板螺栓焊缝开裂研究 总被引:1,自引:0,他引:1
某钢厂将炉前160t铸造起重机的主起升量提高至180t.在增客前,该起重机运行正常,增容后该起重机主小车轨道压板螺栓经常出现松动现象;如果增大螺栓的预紧力则出现螺栓底部环形焊缝开裂的现象.为了寻求引起主小车轨道压板螺栓焊缝开裂的原因,本文采用有限元分析技术进行辅助分析,得出螺栓焊缝开裂的原因. 相似文献
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挤压模在工作时受到的压力很大,这对它的固定夹紧装置提出了较高的要求。目前一般厂家均采用传统的压板螺栓进行夹紧。高等学校本科锻压专业的教材中也只介绍了压板螺栓的夹紧方式。 用压板螺栓作为夹紧装置是过去一线工人们经验积累的体现。随着市场经济的蓬勃发展,科学技术的日新月异,产品的加工方式则是朝着“更快、更好、节能、省材”的方向发展,压板螺栓夹紧方 相似文献
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误区一:螺栓越紧越好 在用螺栓、螺母联接的紧固件中,为防止松动,应保证螺栓、螺母有足够的预紧力,如缸盖螺栓、连杆螺栓、喷油器压板螺栓等,都必须按规定扭矩拧紧,但又不能拧得过紧,否则会造成联接件在外力作用下产生变形、裂纹和凸起,致使结合面不平;同时螺栓还将产生拉伸永久变形,预紧力下降,甚至造成滑扣或折断,引发事故.如有些机手在装配中怕发生冲缸床等故障,拼命拧紧缸盖螺栓,且又不借助扭力扳手,事后引发了不必要的麻烦. 相似文献
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为了校核某型柴油机喷油器的紧固螺栓及压板的强度,建立了喷油器的有限元模型,并将其离散成具有多自由度的系统,利用Abaqus软件分别计算了喷油器压紧螺栓的强度以及喷油器压板的强度和位移,经计算喷油器紧固螺栓及压板的强度满足使用要求。 相似文献
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螺栓压板机构是机械加工最常用的夹紧装置之一,虽然具有结构简单,夹紧可靠等优点,但也有夹紧动作缓慢,效率低等缺点,尤其对于同时使用多个螺栓压板机构,更是如此,下面介绍一种我们设计的夹紧装置,巧妙地利用螺栓压板机构,可快速夹紧工件,其结构如图所示。 相似文献
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《现代制造技术与装备》2015,(1)
偏心轮压板夹紧结构,压板的中部有贯穿压板厚度的沟槽;销轴可在沟槽内沿沟槽的形状的轨迹线运动;第一固定块一边固定在压板的一端上,另一边向垂直于压板的方向延伸;调整螺栓穿过第一固定块并通过调整螺母与第一固定块固定连接;第二固定块垂直于连接板固定在连接板上,并与第一固定块的另一边朝向相同的方向延伸设置;传力螺栓穿过第二固定块并通过设置在第二固定连接块的上表面的传力螺母与第二固定块固定连接;传力螺栓外套设弹簧;弹簧位于第二固定连接块下;传力螺栓的顶端自下而上顶住调整螺栓的底部;传力螺栓的底部与偏心轮外表面相切。本发明的偏心轮压板夹紧结构构造简单,操作方便、夹紧力大并具有自锁功能。 相似文献
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为了研究钢轨波磨对扣件弹条的最大等效应力的影响,以高速铁路使用福斯罗扣件为研究对象,采用有限元软件建立扣件系统有限元模型,采用非线性接触理论,研究不同波磨状态对弹条最大等效应力影响规律,并验证模型。结果表明:弹条与其周围部件之间的接触刚度对弹条的最大等效应力、扣压力与弹条位移没有明显的影响;随着波磨比例系数的增加,弹条后端最大等效应力和应变以高频成比例增大,明显加剧了扣件弹条的疲劳破坏。 相似文献
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Effects of insulated rail joint on the wheel/rail contact stresses under the condition of partial slip 总被引:1,自引:0,他引:1
The effect of insulated rail joint (IRJ) on the wheel–rail normal and tangential contact stress distribution is studied using the finite element method. In this investigation, contact elements are used to simulate the interaction between wheel and rail. Numerical simulations are used to explore the effects of contact distances and materials of IRJ on the contact stress and the maximum shear stress distributions. Numerical results show that the presence of IRJ might significantly affect the wheel–rail contact stress distributions. The results also indicate that Carter's theory is no longer effective in predicting the tangential stress distribution of the wheel–rail contact near an IRJ. The tangential stress causes the location of maximum shear stress shifted toward the rail surface as the wheel–rail contact point moves closer to the IRJ. The maximum shear stress value is more sensitive to a braked force than to a tractive force as the wheel–rail contact point is within the IRJ region. 相似文献
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本文介绍了12m标准轨道衡的主要技术指标、组成原理、以及受力系统等,12m标准轨道衡的研制成功,是国家轨道衡的计量的关键一步,在轨道衡检定和测试中发挥着重要作用。 相似文献
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J. Oda K. Yamazaki H. Yoshida K. Nakada 《International Journal of Mechanical Sciences》1983,25(12):935-944
The clamping effect of rail fastening systems in a travelling crane is studied by theoretical and experimental techniques. For the theoretical model, a model of a unit rail length with a pair of rail fasteners is first considered. The model was idealized to an equivalent spring system composed of many spring elements, and the stiffness constant was formulated. By using this model and the theory of a beam-on-an elastic foundation, the dynamical behavior of the practical rail model with many pairs of rail fasteners was theoretically analyzed. From the results, the changes of the clamping forces in the joint bolts and the rail displacements were obtained and were compared with the experimental values. 相似文献
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应用ANSYS软件建立了钢轨的有限元模型。通过对钢轨模型的有限元分析,得出了不同工况条件下的钢轨上应变场的变化趋势,得到了不同工况处的中性线上节点的数据,并应用数学方法找到了在钢轨中性线上对应变敏感的确切位置。这些数据为以后弹性体的粘贴以及钢轨传感器的设计奠定了基础。 相似文献
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Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding technology has been invented with rotating grinding stones pressed on the rail with defects removal. Such rail grinding works are directed by experiences rather than scientifically guidance, lacking of flexible and scientific operating methods. With grinding control unit holding the grinding stones, the rail grinding process has the characteristics not only the surface grinding but also the running railway vehicles. First of all, it’s important to analyze the contact length between the grinding stone and the rail, because the contact length is a critical parameter to measure the grinding capabilities of stones. Moreover, it’s needed to build up models of railway vehicle unit bonded with the grinding stone to represent the rail grinding car. Therefore the theoretical model for contact length is developed based on the geometrical analysis. And the calculating models are improved considering the grinding car’s dynamic behaviors during the grinding process. Eventually, results are obtained based on the models by taking both the operation parameters and the structure parameters into the calculation, which are suitable for revealing the process of rail grinding by combining the grinding mechanism and the railway vehicle systems. 相似文献
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